High-end bicycles, especially those used for off-road riding, typically have both rear and front suspension systems to assist in traversing uneven or rough terrain. Downhill mountain racing bikes, freeride bikes, trail bikes and recreational bikes can be subjected to high speeds where the bumpier terrain can increase the chance that the rider can lose control. The combination of the terrain and speed conditions can result in rear wheel movement vectors including rearward direction impact vectors in addition to vertical direction vectors.
Many rear suspension systems designed for freeriding and other biking applications are known by those skilled in the art. Such systems generally include a rear suspension permitting a limited degree of travel of the rear wheel relative to the bicycle frame and a rear shock absorber that absorbs or dampens suspension forces acting on the wheel. The range of rear wheel travel permitted by existing suspension systems varies, but is typically within the range of about 5 to 12 inches measured vertically (although some designs permit travel outside this range).
The dramatic growth of rear wheel suspension on such bicycles is partially due to the fact that rear suspension systems not only increases rider comfort, since the suspension dampens jarring forces from rough terrain, but also prevents the forces or movement vectors from being directly transferred to the rider's seat. The growth of these suspensions can also be attributed to the need for increase traction and control when the rear wheel suspension acts to keep the rear wheel in better contact with the trail surface after encountering the rough terrain.
There is a need for improved suspensions for the rear wheel of bicycles and/or two-wheeled vehicle. More particularly, a need remains for suspensions that are adapted or configured for off-road two wheel vehicles (hereafter referred to as bicycles or bikes, including motorized as well as manual powered). The need includes suspensions that allow the rear wheel to move in two axes, or degrees-of-freedom (DOF) relative to the remainder of the frame of the bike.